Long-term Weather Observations Reveal the Impact of Heatwaves on the Yield and Fruit Composition of Cabernet Sauvignon

Effect of heat extremes on the concentration of key grape analytes in Cabernet Sauvignon fruit. Each analyte is reported in a separate panel and respective units are reported on each chart. Differences in heat patterns during the growing season are represented by three clusters: Cluster 1 (C1), Cluster 2 (C2), and Cluster 3 (C3). Points represent averages for individual vineyard blocks and density plots show distributions for each cluster. Across cluster types, gray lines connect averages belonging to an individual vineyard block. Across the board, p values denote statistical significance of cluster effects according to a linear mixed model (fixed effect: cluster; random effect: vineyard block ID) and letters denote differences across means by clusters according to Tukey’s adjusted post-hoc test (p ≤ 0.05). IBMP, 3-isobutyl-2-methoxypyrazine; TSS, total soluble solids; YAN, yeast assimilable nitrogen.